The Sidewalls

Above the basal pedestal, the sidewalls rise to meet the upper surface and actively growing lip of the cup reefs. On the nearshore cup reefs, the sidewalls are sharply undercut whereas on the deeper offshore forms, they slope inward to a lesser degree.

On the sidewalls of the offshore cup reefs, coralline algae, anthozoans, hydrozoan, bivalves and other organisms of the coral reef fauna are found, whereas, on the nearshore cup reefs, the fauna is mainly red coralline algae, bryozoan, Millepora spp., Homotrema rubrum, and non-calcareous brown algae.